Cryosurgical instruments



Sheet of 3 Filed Feb. 3, 1967 .INVENTOR.

June 24, 1969 v. A THYBERG 3,451,395

CRYOSURGICAL INSTRUMENTS Filed Feb. 5. 1967 IN V ENTOR.

June 24, 1969 v. A. THYBERG CRYOSURGICAL INSTRUMENTS Sheet 3 Of3 Filed Feb. 5, 1967 m 3 w .QRIP

INVENTOR.

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JII'IURNEYS.

United States Patent 3,451,395 CRYOSURGICAL INSTRUMENTS Victor A. Thyberg, Fairfield, Conn., assignor to Frigitronics, Inc., Bridgeport, Conn., a corporation of Connecticut Filed Feb. 3, 1967, Ser. No. 613,800 Int. Cl. A61b 17/36 US. Cl. 128303.1 9 Claims ABSTRACT OF THE DISCLOSURE A cryosurgical probe having a metering orifice through which liquid refrigerant flows and expands into a boiler tip for cooling the tip under normal operating conditions. A control lever is provided for opening a valve to flood the boiler with liquid refrigerant for warming the tip. The valve is delicately and adjustably balanced so as to require application of a very small force upon the control lever to open the valve.

This invention relates to a cryogenic medical apparatus which may be used for eye surgery and, more particularly, to a cryogenic surgical probe which is normally cold when in use and may be rapidly warmed without electrical means.

Cataract surgery is one of the most delicate of surgical procedures as it involves the removal of an opacified lens, the wall or capsule of which has extremely low tensile properties and is easily ruptured. 'Usually, cataracts are extracted whole (intracapsularly) through an incision made at the intersection of the cornea and the outer edge of the iris. The lens is usually removed by the exertion of traction on the capsule by means of forceps especially designed to grasp the lens or by means of a suitable suction device. These methods have been found to be unsatisfactory as they sometimes result in rupture of the capsule, and contamination of the healthy parts of the eye by the lens fluid.

To prevent rupture of the capsule, it has recently become the practice in some hospitals to perform this operation by placing a cryosurgical instrument against the lens to lower the temperature of the lens to approximately 30 C. thereby producing an ice mass in the interior of the lens which makes an adhesive bond between the instrument tip and the capsule. With the lens thus adhered to the instrument, the surgeon may exeit traction on the lens, the tractive force thus being distributed over the surface of the intralenticular ice mass which has become an integral part of the instrument, thereby appreciably reducing the traction on the capsule itself. In cases in which the capsule has already been ruptured, or in which it ruptures during extraction, it is possible to seal the rupture by placing the cryosurgical instrument over the tear in the capsule, thus solidifying the intralenticular fluid, and to continue with the intracapsular extractioin in the same manner as with an unruptured lens.

Various cryosurgical instruments have been developed for utilizing the techniques of cryosurgery. Machined metal probes externally cooled by insertion into a mixture of alcohol and Dry Ice are a simple form of such instruments and are of very limited practicability. Other forms of these instruments include thermoelectrically refrigerated probes based on the Peltier effect, low temperature liquid circulating probes, and boiler types probes within which low boiling temperature liquids are caused to vaporize.

The type of cryosurgical instrument to be used is determined to a great extent on the type of operation to 3,451,395 Patented June 24, 1969 be performed. For example, for complicated cataract removals continuous operation of the instrument is required for a relatively long period of time, since the surgeon may be required to be in the eye for as long as fifteen to twenty minutes. Therefore, it is obvious that the externally cooled instruments would be useless, disposable units would have exhausted their charge in the first few minutes of actual use, and 'thermoelectrically cooled instruments which are necessarily large, may tire the surgeons hand over such an extended period of use.

A cryosurgical instrument of the boiler type is described in application Ser. No. 516,383, filed Dec. 2.7, 1965, now Patent No. 3,393,679, invented by Ralph'E. Crump and Frank L. :Reynolds and assigned to the same assignee as this application. Therein was disclosed a cryosurgical instrument for use in the treatment of detached retina. The instrument of that invention is inserted normally warm, as it must be passed through or by healthy tissue to reach the operating site. Furthermore, in performing the retinal attachment, it is only necessary to reach a very low temperature for a relatively short time in order to weld the detached retina to the wall of the eye. Thus, a unique method and apparatus was disclosed therein for rapidly cooling the normally warm instrument tip in response to the depression of a control lever when the surgeon desired to change the state of the instrument.

Since the instrument of the present invention is designed for use in cataract extraction operations wherein it must be maintained at a low temperature for a long period of time while removing the lens from the eye, it would be impractical for the surgeon to use a probe of the type described in the copending application as his hand would become tired after a relatively short period of time if he were required to maintain a control lever depressed. Therefore, the instrument of this invention must be normally cold when in use and must be able to achieve rapid warming if, for example, the surgeon should inadvertently touch some portion of the body other than that to which the low temperature is meant to be applied. Since the probe tip will freeze and adhere to any moist portion of the body to which it comes in contact, it is necessary to be able to rapidly warm the tip by finger actuating a control means that is so delicate in operation that its actuation will not cause appreciable movement of the instrument and tear the tissue to which the instrument is frozen.

Accordingly, it is the primary object of this invention to provide an improved cryosurgical instrument designed especially for cataract extraction operations, which will be normally cold when in use and may be rapidly warmed by the application of a very slight force supplied by the surgeons finger to a control means.

Another object is to provide a cryosurgical instrument which is safe for operating-room use, being completely explosion-proof by virtue of having no electrical switches, lights, plugs, or heating elements.

Still another object is to provide such an instrument which is small and not too unlike instrument shapes and sizes with which the opthalmic surgeon is familiar, and further having a non-electrical warming control means which can be adjusted to respond to the application of any desired force.

To accomplish these objects, in one form, a cryosurgical instrument is provided which comprises: a body or handle; a tip member secured to the forward end of the handle and defining a low temperature boiler; a liquid refrigerant delivery means; a fluid exhaust means; a delivery tube located at the interior of the body communicating between the delivery means and the boiler; a longitudinally movable exhaust tube located within the body; an expansion valve metering orifice located between the delivery tube and the boiler for causing the liquid refrigerant to vaporize as it flows therethrough, and to cool the boiler; an inlet valve and an exhaust valve located at the remote ends of the exhaust tube; actuating means for moving the exhaust tube for substantially simultaneously opening and closing the respective valves; and an adjustable balancing means for urging the inlet valve closed so that the bias may be overcome by application of a slight force to the actuating means.

Other objects and further details of that which I believe to be novel and my invention will be clear from the following description and claims taken with the accompanying drawings, wherein:

FIG. 1 is a perspective view of the cryosurgical instrument of my invention connected to a liquid supply cabinet;

FIG. 2 is a plan view of the instrument of FIG. 1 constructed in accordance with this invention;

FIG. 3 is a side elevational View of the instrument of FIG 2;

FIG. 4 is an enlarged cross sectional view of the instrument when the control level is in its normal position;

FIG. 5 is an enlarged cross sectional view of the instrument when the control level is depressed;

FIG. 6 is an enlarged cross sectional view of the tip, or boiler, of the instrument;

FIG. 7 is a sectional view taken substantially along the line 77 of FIG. 6;

FIG. 8 is an enlarged sectional view of the control lever operator and the force adjusting means;

FIG. 9 is a sectional view taken substantially along the line 9-9 of FIG. 8;

FIG. 10 is an enlarged perspective view of the spring tensioning device;

FIG. 11 is a schematic view showing the probe in use during a cataract extraction operation; and

FIG. 12 is an enlarged view of a portion of a set of locking pins of various sizes.

Referring to the drawings, there is illustrated in FIG. 1 a liquid refrigerant delivery cabinet C carrying a refrigerant supply bottle B. A cryosurgical instrument P is connected to the delivery cabinet by the supply tube T S and the exhaust tube T The bottle B may contain any conventional liquid refrigerant, such as those refrigerants marketed under the trademarks Freon 12, Freon 502, Freon 22 (a mark of Du Pont) or uKon (a mark of Union Carbide Corporation).

With particular reference to FIGS. 2-10 there is illustrated in detail the cryosurgical instrument P shown in perspective in FIG. 1. The probe comprises a main body handle portion 10 and a tip portion 12 secured to the forward end thereof. The handle 10 includes a tubular portion 14 extending approximately two-thirds of its length at the forward end thereof, and a larger portion disposed at the rearward third of the handle, defined by spaced upstanding walls 16. A control level 18 overlies the handle portion 10 and is pivotally secured to the handle between the spaced walls 16 by means of pivot pin 20.

The rearwardmost end of the handle 10 carries an end Wall 22 (FIGS. 4 and 5) which is welded in place or secured thereto in some other suitable manner. The end wall 22 includes tapped holes 24 and 26 for receiving an inlet coupling 28 and an exhaust coupling 30. The inlet coupling is provided with a micron filter 32 for preventing contaminating particles from entering the liquid supply line of the surgical instrument. The inlet coupling 28 is bored to received a delivery tube 34 which tube extends substantially through the length or the handle and terminates in a welded joint in an inclined passage 36 formed in a front support block 38. Block 38 comprises an annular member located at the forwardmost end of the handle 10 and secured therein by being stopped against a ring member 40 which in turn is welded within the tubular portion 14 of the handle 10. The annular block 38 further includes an internally threaded portion 42 at this forward end and an annular boss 44 at its rearward end.

The tip portion 12 is threadedly coupled with the threaded portion 42 and comprises a conical member 46 having an annular externally threaded boss 48, and a bore 49 through which a thin walled tube 50 is extended. In order to prevent the tube 50 from being displaced or removed from its position under the influence 0f the high pressure liquid refrigrant, a collar 52 is soldered to the tube or secured thereon in some other suitable manner for abutment with the end of the boss 48. The forwardmost end of the sleeve 58 is necked down at 54 (FIG. 6).

The tip 12 further comprises the boiler 56, a curved thin walled tube, closed at one end 57 and enlarged at its remote open end 58, which is captured by the necked down wall portion 54 of the tube 50. A protective sleeve 59 of a plastic material such as that marketed under the trademark Tefion (a mark of Du Pont) is disposed upon the surface of the tip 12 from the forward end of the conical member 46 to the forward end of the probe, exposing only the end 57 of the boiler 56. The enlarged end 58 of the boiler includes a precision machined conical inlet valve seat 60 which cooperates with a conical inlet valve 63 which is secured firmly in the forwardmost end of an exhaust tube 64. A machined metering orifice 62 is located upon the concial exterior surface of the inlet valve 63, the orifice serving as an expansion valve for vaporization of the liquid refrigerant. The exhaust tube 64 is located coaxially with an internally of the tube 50, and the annular front support block 38 and extends substantially the entire length of the handle 10, being movable longitudinally relative thereto.

A liquid refrigerant reservoir 65, located at the forward end of the handle 10, is defined by the outer surface of the exhaust tube 64, the inlet valve 60, 63, the inner surface of the tube 50, the inner surface of the annular front support block 38, a bellows member 66 and a front spring stop 68 which is welded to the exhaust tube 64 for longitudinal movement therewith. The bellows 66 is secured in some suitable manner to the bosses 44 and 69 formed on the annular front support block 38 and the front spring stop 68 respectively. It is apparent that as the pressurized liquid refrigerant enters the reservoir through the delivery tube 34 it Will fill the reservoir including bellows 66 and tend to move the front spring stop 68 and exhaust tube 64 in a rearward direction. To counteract this tendency, a compression spring 72 is mounted between the movable front spring stop 68 and a stationary rear spring stop 74, the spring 72 being mounted upon the bosses and 73 of the front spring stop 68 and the rear spring stop 74, respectively. The compression spring 72 can be pre-set to deliver a predetermined forward working force responsive to the location of the rear spring stop 74 as determined by the dimensions of a pair of 'locking pins 76 and 78.

It can be clearly seen in FIG. 10 that the rear spring stop 74 comprises a partially cylindrical movable body including a spring supporting boss 73 and defining a central axial bore 73' of a diameter large enough for passage of the exhaust tube 64 therethrough. The spring stop 74 further defines opposed planar side wall portions 80 having inclined shoulders 82 for engagement with the pair of locking pins 76 and 78, and a planar top wall portion 84 for allowing the delivery tube 34 to pass between the stop 74 and the interior wall of the tubular handle 14 (see FIG. 8). The locking pins 76, 78 include wedge-shaped lower portions 86 for interlocking on the taper with the inclined shoulders 82, for preventing inadvertent removal of the pins. The pins 76 and 78 are made for insertion in grooves 98 (FIG. 9) defined in the upstanding walls 16 of the handle and further include enlarged portions 88 designed to conform to the forward end of the upstanding walls 16. The locking pins 76 and 78 also include bevelled wall portions 90,

92, 94 (FIG. for preventing interference of the locking pins with the cylindrical body members at the interior of the tubular handle. It should be understood at this point that adjustment of the forwardly directed compression spring working force is determined by the location of the stationary rear spring stop 74 as determined by the size of the pair of locking pins 76 and 78 which are inserted in the grooves 98 of the upstanding walls 16.

The exhaust tube 64 extending through the rear spring support 74 carries a pressure block 100' (FIG. 5) at its rearwardmost end. Pressure block 100 comprises a substantially cylindrical body having a boss 102 at its forwardmost end defining a bore 104 for snugly receiving the exhaust tube 64. Communicating with the bore 104- is an enlarged bore 106 extending through the remainder of the pressure block 100 for snugly receiving a tubular valve member 108 therein. An exhaust valve member 110 includes a positioning spindle 111 for centrally locating the tubular valve member 108 with respect to a conical valve seat 112 which cooperates with the valve member 108 for controlling the flow of the exhaust gases through the surgical instrument. The exhaust valve member 110 further includes an externally threaded elongated tubular coupling portion 114 for threaded engage ment in the end Wall 22. The member 110 also has an internally threaded portion 116 for threadedly receiving the exhaust coupling member 30 of the exhaust tube T,,. A plurality of radial ports 118 are defined by the tubular coupling member 114 for communication between an exhaust gas chamber 120 and the exhaust coupling 30. The chamber 120 is enclosed by a bellows 122 which is secured at one end to the pressure block 100 and at its other end to an annular boss 124 disposed on the end wall 22. Exhaust gases are discharged through the exhaust valve 108, 110 into the exhaust gas chamber 120 from which they are discharged through ports 118 to the atmosphere or withdrawn by a suitable pumping means.

The control lever 18, overlying substantially the entire handle 10, comprises a narrow lever arm seated between the upstanding walls 16 having a finger receiving curved forward portion 126. It is pivoted near its rear to provide the surgeon with a substantial mechanical advantage. A pivot block 128 in control lever 18 is bored to receive a pivot pin 20 which passes through one of the upstanding walls 16, through the pivot block 128 and is threadedly engaged with the outer wall 16. The pivot block 128 further comprises a pair of bifurcated legs 132 extending into the handle, between which the delivery tube 34 may pass, and which extend to a position adjacent the pressure block 100 for moving the pressure block 100 rearwardly when the control lever is depressed (see FIG. 6). The rearward movement of the pressure block causes the exhaust tube 64 carrying the front spring stop 68, to move in the same direction, thus further compressing the spring 72. Upon release of the depressing force from the control lever 18, it will return to its upward position (see FIG. 4) since the exhaust tube 64 carrying the pressure block 100 will be moved forwardly by the compression spring 72. The control lever 18 further includes a resilient pad 134 at its rearwardmost end for acting as a bumper for preventing damage to the delivery tube 34 and the inlet coupling when the lever is returned to its upward position by the compression spring 72.

Operation Warm liquid refrigerant at room temperature flows from the bottle B, seated in the cabinet C, through the supply tube T and enters the rear section of the surgical instrument through the inlet coupling 28 which is threadedly engaged in the rear wall 24 of the instrument. The warm liquid is piped to the front section of the instrument through an internal delivery tube 34, and enters the liquid refrigerant reservoir 65, wherein it forms an annulus which acts as a thermal insulator for protecting the hand of the surgeon and the adjacent eye tissue from freezing temperature. This comparatively large volume of near-stagnant liquid refrigerant also serves as a capacitor for preventing surging of the liquid as it is metered into the boiler 56.

The amount of liquid refrigerant which is metered to the boiler 56 through the precision machined metering orifice 62 is exactly regulated to effect the required low degree of temperature and rate of freeze, the two important parameters necessary for cryogenic surgery. Careful regulation of the liquid refrigerant flow is necessary so as to form a steady state intralenticular iceball within a few seconds after application of the instrument to the lens. It is desirable to freeze only approximately 25% of the lens fluid since, if the lens volume is excessively frozen, the vitreous v and adjacent tissues, such as the iris i and the zonules z (FIG. 11), may be damaged. Therefore, as has been noted, the metering orifice 62 has been precisely machined in the conical inlet valve 63. The inlet valve is held closed by the force of the compression spring 72 which biases the conical inlet valve 63 carried by the exhaust tube 64 axially forward into the conical inlet valve seat 60. When the inlet valve 63 is closed, the exhaust valve 108, is opened through exhaust tube T to the atmosphere or to a suitable vacuum pumping means. This causes the liquid refrigerant entering the boiler 56 through the metering orifice 62 to expand and to vaporize. This expansion and change of state reduces the temperature of the refrigerant.

The pressure of the refrigerant in its liquid phase (approximately lbs. per square inch at 70 F.) has a tendency to expand bellows 66 and move the front spring stop 68 rearwardly, therefore the spring force is adjusted to overcome this rearward bias and maintain inlet valve 63 normally closed. The near equilibrium condition between the fluid pressure force and the spring force which maintains the inlet valve closed is necessary in order to provide a delicately balanced surgical instrument. By depressing the lever 18 with a force so small that the tip of the instrument itself will not be moved downwardly to displace the tissue to which it is frozen, the delicate equilibrium condition may be overcome by the surgeon for opening the inlet valve 63, flooding and rapidly warming the boiler 56. The compression spring 72 is compressed to deliver a predetermined forward working force which is adjustable. Such an adjustment is made by removing the pair of locking pins 76 and 78 and replacing them with a larger or smaller pair of pins selected from a set of locking pins of various sizes (see FIG. 12) which may be interposed between the rear spring stop 74 and the upstanding walls 16 of the handle within the grooves 98. Of course, access to the rear spring stop 74 is blocked by the control lever 18 which must be removed prior to the insertion of a special tool which aids in displacing the rear spring stop 74 for removal of the locking pins 76 and 78 and reinsertion of a different pair.

FIG. 11 illustrates the cryogenic instrument in use during a cataract extraction operation. The surgeon has made an incision in the cornea c and lifts the cornea away from the lens in order to introduce the exposed tip of the instrument to the lens I. The instrument is allowed to remain in contact with the lens 1 before beginning the extraction, in order to adhere the tip 5 7 of the instrument to the lens wall or capsule w and for forming an intralenticular iceball b which assists in the distribution of the tractive force over a greater area of the capsule w. The instrument is then raised, thereby stretching the zonules z in order that a tool may be inserted to rupture the zonules prior to extracting the lens 1. After the zonules 2 have been ruptrued, the lens may be completely extracted. It should be noted that the Teflon sleeve 59 which protects the forward end of the instrument, leaving only the tip exposed, prevents adhesion of the instrument to any portion of the eye to which it may come incontact. Should the iris i, cornea c or any other part of the eye inadvertently be contacted with the tip 57 of the instrument, the control lever 18 may be depressed, thereby warming the tip and allowing the instrument to be released.

It is to be understood that the present disclosure has been made only by way of example, and that numerous changes in details of construction and the combination and arrangement of parts may be resorted to without departing from the true spirit and scope of the invention as hereinafter claimed.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A cryosurgical instrument which comprises: a body member; a tip member secured to one end of said body member defining a low temperature boiling chamber; fluid supply means for delivering a fluid to said body; means for exhausting a fluid from said body; a delivery tube in fluid flow relationship between said fluid supply means and said boiling chamber; means defining a metering orifice located between said delivery tube and said boiling chamber for allowing the fluid to vaporize and to cool said boiling chamber; inlet valve means for communieating said delivery tube with said boiling chamber; an axially movable exhaust tube disposed within said body in fluid flow relationship between said boiling chamber and said fluid exhausting means; exhaust valve means for communicating said exhaust tube with said fluid exhausting means; actuating means for opening and closing said inlet valve means while simultaneously closing and opening said exhaust valve means; and balancing means disposed within said body for urging said inlet valve closed for allowing said actuating means to be operated in response to the application of a very slight force.

2. The cryosurgical instrument defined in claim 1 wherein: said exhaust tube extends from an inlet valve seat to an exhaust valve seat, and comprises an inlet valve disposed at a first end and an exhaust valve disposed at a second end; and means for axially moving said exhaust tube in response to the movement of said actuating means for opening and closing said inlet and exhaust valves.

3. The cryosurgical instrument defined in claim 1 wherein said balancing means comprises: rearward axial force exerting means; forward axial force exerting means; and a forward stop member firmly secured to said exhaust tube upon which said axial force exerting means operate for maintaining said stop member biased in a forward direction for maintaining said inlet valve closed.

4. The cryosurgical instrument defined in claim 3 wherein said rearward axial force exerting means is an expansible pressure chamber responsive to the introduction of pressurized fluid through said delivery tube.

5. The cryosurgical instrument defined in claim 3 wherein: said forward axial force exerting means is a compression spring; and further comprising a rear stop member adjustably axially positionable within said body and supporting one end of said compression spring, the other end of said compression spring biasing said first stop member forwardly.

6. The cryosurgical instrument defined in claim 5 further including positioning means selectively axially locating said rear stop member.

7. The cryosurgical instrument defined in claim 6 wherein said positioning means comprises a set of pairs of locking pins of different sizes selectively replaceable with one another positioning said second stop member either closer to or further from said first stop member for varying the forward axial force exerted by said compression spring.

8. The cryosurgical instrument defined in claim 5 wherein: said rear stop member comprises a body defining planar opposed side wall portions, each wall portion having a shoulder inclined with respect to the longitudinal axis of said body member; and further including axial positioning means comprising a pair of wedge-shaped locking pins each engaging said rear stop member at one of said inclined shoulders, for preventing inadvertent removal of said locking pins.

9. The cryosurgical instrument defined in claim 1 further comprising: a pressure block firmly secured to said exhaust tube for axial movement therewith; and wherein said actuating means comprises a control lover overlying said body, mounted thereon for pivotal movement with respect thereto, and having force applying means thereon for moving said pressure block axially in response to a slight force applied to said lever for overcoming said balancing means.

References Cited UNITED STATES PATENTS 3,298,371 1/1967 Lee 128303.l 3,333,587 8/1967 Johnston 128303.1 3,351,063 11/1967 Malaker 128303.1 3,393,679 7/1968 Crump 128303.1

RICHARD A. GAUDET, Primary Examiner.

JOHN D. YASKO, Assistant Examiner.

US. Cl. X.R. 62-293 M050 UNITED .I JIES PATENT OFFICE 5/69) 1 n h Tm CERTIFICJrE Or (lonr-rnCTrr/"N Patent No. '3 451 3Q) Dated June 2 44 1969 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column M, line 1, cancel "this" and substitute --its-.

See page 7, line 17 of specification as filed.

ColumnB, line 14, before "positioning" insert -for--.

See line 4 of claim 7 as filed.

SIGNED mo suuzo APR 2 8 I970 u Attest:

WIILIAM E. summm, m. Attesting Officer Commissioner of Patents 

